Paleolimnological records for tracking dam-induced changes in the composition and supply of sediment to middle Yangtze floodplain lakes

•Sedimentary records were explored in five lakes of the middle Yangtze reaches.•Decreases in K/Al ratios mainly respond to reduced riverine inputs after damming.•Recent increases in organic matter content indicate rising aquatic production.•These phenomena might be widespread in other similar floodplains worldwide.